There are conventionally known devices that collect information from a plurality of robots connected to a communication network, thereby predicting a failure in the robots (for example, see Japanese Unexamined Patent Application, Publication No. 2004-202624). Furthermore, there are known devices that predict a failure by using information from a vibration sensor that is provided at a working end of a robot (for example, see Japanese Unexamined Patent Application, Publication No. Hei 05-52712).
As in such a device, in a case in which information is collected from a robot or from a sensor provided on a robot, such information often contains environmental-factor noise, such as noise due to vibrations from a forklift passing near the device, fluctuations in the power-supply voltage, or a processing machine, for example. In general, in order to remove such environmental-factor noise, a filter is applied to a signal containing the information from the sensor.